1. Technical Field
The present invention relates generally to electronic device packaging; and, more particularly, it relates to surface acoustic wave filter packaging on a multi-chip module.
2. Related Art
Traditional surface acoustic wave filters are available in relatively expensive ceramic packages. These ceramic packages are expensive not only in terms of initial cost, but they are expensive in terms of subsequent costs such as mounting and subsequent packaging and integration of them into larger scale devices. This relatively expensive purchase cost of conventional surface acoustic wave filters is mostly attributed to the relatively complex packaging of the surface acoustic wave filter that must be performed to ensure its proper performance once it is subsequently integrated into a device. Typically, the surface acoustic wave filter itself in fully enclosed in a ceramic package that itself contains contact pads such that the entire package is capable of being mounted on a substrate. The ceramic package contains, inside of the ceramic package, sufficient space so that the surface acoustic wave filter can properly propagate surface acoustic waves without obstruction. While the operation of these conventionally packaged surface acoustic wave filters is adequate, the cost of procuring them is often prohibitively high for their integration into certain low cost applications. In addition, even for some applications that have the overhead to accommodate their relatively high purchase price, the subsequently associated cost to incorporate them into a device is another cost barrier that must be overcome. These ceramic packages are typically hermetically sealed and surface mounted into their respective devices, and the handling of the relatively delicate ceramic packaging increases the cost of the overall integration of the device into which it is to be installed.
Absent the use of a surface acoustic wave filter that comes pre-packaged in a packaging such as the ceramic packaging described above, the surface acoustic wave filter is commonly incapable of being included into an end product that is to be encapsulated. This is because, using traditional packaging methods, the operation of the surface acoustic wave filter will be greatly compromised by the encapsulation process. This is largely due to the fact that after the encapsulation process has been performed, the surface acoustic waves are unable to propagate on the surface acoustic wave filter due to the obstruction of the material applied during the encapsulation process.
One major problem facing the incorporation of conventional surface acoustic wave filters is how to protect the surface of a surface acoustic wave filter such that it can operate properly even after encapsulation of the surface acoustic wave filter once it has been mounted into a device. Absent the use proper packaging of a surface acoustic wave filter using methods described above such as the ceramic packaging, the conventional art of including surface acoustic wave filters into devices does not permit their proper operation. In addition, the cost associated with their inclusion into many devices is often excessive and prohibitive of their incorporation into various devices. A method to incorporate such devices into so that the difficult cost margins are adequately met simply does not exist in the art. Also, the conventional manner in which surface acoustic wave filters are packaged, in ceramic, is inherently consumptive in real estate on a motherboard or other circuit board, in that, the surface acoustic wave filter requires a fixed amount of space on the board.
Further limitations and disadvantages of conventional and traditional systems will become apparent to one of skill in the art through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.